In recent years, the substantial increases in the energy costs of heating and cooling has encouraged the development of new and better insulation materials and many new insulation materials have been developed in an attempt to satisfy this need.
One of the recently developed materials has been fiberglass insulation. The known methods for producing fiberglass insulation has required, because of the relatively short glass fibers produced, the use of organic resin adhesives.
The use of organic resin adhesives to make fiberglass insulation has limited the use of the fiberglass insulation to temperatures of 200.degree. to 400.degree. F. at which the adhesives decompose.
The conventional methods of making glass fibers for use in making fiberglass insulation also suffer the disadvantages of requiring the use of relatively large amounts of energy to manufacture a given amount of fibers and/or requiring large capital investments in fiber blowing apparatus.
The known methods for producing glass fibers for insulation have not been successful in producing microfilaments of relatively long length at an economical cost.
One of the known methods of producing glass fibers is described in Mukai et al. U.S. Pat. No. 4,166,656. The Mukai et al. patent describes a method of using a coaxial nozzle to discharge a hollow molten stream of glass while continuously blowing a gas at the hollow stream of glass to press, extend, smash and blow away the molten stream of glass. As a result, the molten glass stream is finely broken up into relatively short fibers. The Mukai et al. patent does not produce the relatively long glass fibers produced in accordance with the present invention.
In addition the recent substantial increases in costs of basic materials such as plastics, cement, asphalt and the like has also encouraged development and use of reinforcing filler materials to reduce the amount and cost of the basic materials used and the weight of the finished materials. One of the suggested filler materials utilizes glass fibers. The present invention which produces relatively long glass filaments at an economical low price provides an improved glass filament material for use as a filler and reinforcing material.
Further, the use of conventional fiberglass materials for insulation is being questioned in the light of the recently discovered possibility that fiberglass of certain particle size may be carcinogenic in the same or similar manner as asbestos.
In addition, in some applications, the use of conventionally produced fibers for fiberglass production and/or fillers presents a potentially serious problem because they are difficult to handle since they are readily elutriated and tend to blow about. In situations of this type, the relatively long microfilaments of the present invention provide a convenient and safe method of handling the microfilaments.
Thus, the known methods for producing glass fibers for fiberglass insulation and/or fillers have not been successful in producing relatively long glass fibers or in producing long glass fibers at relatively low economical costs and energy requirements.